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Check out &quot;Reply #274&quot; on that Thread.... that is a Test Load for
a Red LD... add 2 more diodes for a Blu-Ray Test Load...

Connect a 1 Ohm Resistor in series with your Test Load and measure
the voltage across it when your Driver is running.... (1mV=1mA)
A 1 mV reading is equivalent *to 1mA of current through the Test load...

I hope you use a test load for your circuit first, so that you know how much to set the current to, and whether the circuit actually works. You won't want to fry your diode while testing it for whether it works or not. (If not, you'll get two results: It doesn't work, or it did. Either way, it's not now!)

Also, be carful when soldering the LM317. Don't let it get too hot! IC chips can't stand heat very well, although better than laser diodes. Clip on a large piece of metal to the back of the LM317 while soldering (I used a pair of scissors)

And, I'd recommend starting around 30mA, increasing to 100mA maximum without a heat sink. 30mA is to check whether it works, and 100mA is to check whether it's worth keeping. If a red diode can't stand even 100mA, not really much use compared to a 5mW pointer which uses less current and serves the same job.

On top of that, remember to discharge the capacitor after you disconnect the battery from the cirucit. A wire across the capacitor terminals will do. Some people have fried their laser diodes accidentally when somehow, the capcitor had remained charged, and contacted the diode giving a pulse of laser light that marked the final cry of the diode.

Btw, don't triple or double post. There is a function to edit your posts which can be accessed through the &quot;Modify&quot; button.

Yes, you can bend the pins, they're just wire. Just don't do it too much or they'll break off.

The 1 Ohm resistor is so your multimeter is not in line with the current path. This can be bad because you don't know how the circuitry in the DMM will affect the circuit as a whole. In addition, some cheap DMMs only go up to 200mA, whereas their voltage measurements can go higher. Finally, there is a risk that you might burn out your DMM, or at least blow out its fuse, if there is a large current spike. This can come from the circuit layout, or more frequently, if you accidentally forget to switch the cables when measuring something else like voltage (the current measurement is like a wire, which can cause a short in a circuit).

You know, you might want to invest in some good parts and equipment, as well as some more knowledge, before you accidentally blow out your more expensive components (the laser diodes). I'd go on Mouser.com and buy like $10-$20 worth of components. This can include a variety of resistors, diodes, caps, etc. That way you don't have to worry about burning out some, or lacking them. It sure beats burning out your $15 laser diode, or $30 DMM.

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